Signaling system



lDec. 15, 1925- v H. P. CLAUSEN SIGNALING SYSTEM Filed De. e, 1.923

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/m/effaf y #n/f E CML/sen Patented Der.. 15, 1925.

UNITED STATES `PA'rErVr ortica.

HENRY P. CLAUSEN, OF MAMARONECK, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION NEW YORK.

s IGNALrnG' SYSTEM.

Application led December 6, 1923. Serial No. 678,937.

To all whom t may concern.'

Be itknown that', I, 'HENRY P. CLAUsnN, a citizen of the United States of America,- residing at Mamaroneck, in the county of Westchester and "State of" New YYrlgfhave invented certain new' and useful Improvements in Signaling Systems, of which the following is a full, clear, concise, and exact description. l

This invention relates to' signaling systems, and more particularlyto such systems in which vacuum tubes vor their equivalent `form a part.

An object of the invention is to vary the potential applied to the grid and plate electrodes of a vacuum tube without varying the filament current.

' In accordance with the above object, the

present invention contemplates the provi` 20 sion in the filament circuit of a vacuum tube of a double rheostat having a single control element lfor' changing the potential of the grid or plate electrodes or both ywithout varyingv the filament current.

` Inthe drawing, Fig. 1'illustrates one embodiment of the invention; Fig. 2 shows the circuit connections for lcausing variations in the potential applied to the plate electrode;

Fig. 3 illustrates the circuit connections for causing variations in the potential applied to the grid electrode; while Fig. 4 illustrates a modification of the arrangement shown in Fig. 1.

- In Fig. 1 there is shown 'a radio receiving set consisting of a stage 'of radiofrequency amplification, a detector and a stage of audio-frequency amplification 4with a translating device associatedwith the stage of au dio-frequency amplification.

vThe antenna 5 may be either of the aerial type or the loop type. i The antenna 5 is grounded through amadjustable condenser 6, an inductance 7 andthe primary winding of an adjustable inductive coupling 8. Connected to the secondary winding of the inductive coupling 8 is a thermionic device 9 serving to amplify the Waves of the radio frequency. In order to improve the `"selectivity. of the circuit, thus allowing-its use `with all wave lengths, an adjustable condenser 10 is connected in the input circuitof the thermionicfdevice 9.

Inductively coupled through a transformer 14 is a thermioriic -device 15 which' functions as a detector or rectifier of the .the audio-frequency signals.

. phone receiver 20.

waves of' the radio frequency impressed thereon through the operation of the thermionic device 9. In addition to the thermio nic devices 9- and 15, a third thermionic device 19 is inductively'connected Vto the" thermionic device- 1 5 by meansof a transformer 18. The thermionic device 19 is devices are heated by parallel connections from a battery 24, while potential for the plate electrodes of the varioustubes is sup-- plied from a battery 25 whichhas various taps for giving the desired potentialsfto the respective thermionicdevices. i

Connected in each ofthe filament` circuits is a double rheostat witha single control element. Each of these rheostats comprises a pair ,of resistances 26 and ,27 and a pair of spring V-members 28 and 29. These spring members are suitably fastened to a supporting member 30 which may be moved inorder' to Vary the resistances 26 and 27. l Itis apparentfrom the drawing that should the supporting member 30 be moved, say in an upward direction, theresistance in the'filam'entcircuit will be maintained` constant. Although the movement ofthesupporting member 30 in an upward direction increases the amount of resistance 26 connected in the circuit, a correspondingr decrease in the resistance 27 results. Consequently, fthe current in the filament k21 lis maintained constant. However, the movement of the supporting member 30' in this. manner :varies the potential applied between theffilament 21 andthe grid electrode 22 as well as between the filament and the plate electrode 23.

When the spring members 28 and 29 are in their lowerniost position, all'of. the resistance 26 is disconnected while all of the .resistance 27 is connected in the filamentcir cuit. In this position of the switch, the potential difference between grid and nega tive end of filament is equal to the drop in resistance 27 Now in the case of the plate electrode 23, since all of the resistance 27 is connected in the filament circuit, the potential of this electrode with respect to negative end of the filament will be at the potential of the plate battery plus the drop in the filament.I It is thus seen that when the supporting member 30is moved so that the grid electrode 22 becomes less negative, the

plate electrode 23 is in turn made morepositive and vice versa. The same result rs obtained by operating the rheostats in the amplifiers 9 and 19.

In the case of detector devices, 1t`1s de sirable to work on the most critical part of the curve characteristic, that is, at a point-` where the largest difference in amplification is produced. With the arrangement previously described. the potential of .the grid electrode may be varied to shift ,the position on the curve characteristic at Which'the d'evice is operated, therefore enabling betterV not operatingv on the most efficient part .of

the curve characteristic, the potentialof the grid electrode may be varied to brmg about the most satisfactory operating condition.

Referring now for thexnoment to Fig. 2, a

. vacuum tube 32 havinga cathode 33, a grid .Y electrode 34 and a plate electrode 35, is inductively connected to an antenna 36 by means of 'an adjustable inductive coupling 37. Apparatus similar to that described in connection with' Fig.` 1 is included'in the antenna circuit as well asa condenser in the secondary circuit of the inductivecou ling.

In the arrangement shown in this `gure,

however, the grid electrode 34 is connected to a resistance 38 which is connected betweenA the terminals of the filament 33 and which is connected to the spring members of a rheostat 39 identical to thatdescribed in connection with the thermionic device 15. The plate electrode, 35 of this thermionic device 32 is'connected through telephone receivers 40to the positive 'pole of battery 41 and to l the right hand resistance of the rheostat 39.

When-the rheostat 39 is moved in an'upward direction, the filament current is maintained constant, while the grid electrode 34 is maintained at a potential correspondingl to the potential of the filament. However,

in the case .of the vplate electrode, the potential. is varied in accordance with the changes in the right hand resistance of the rheostat 39. TIitl: such an arrangement, the potential oi lthe plate electrode may be 'varied the greatestvmuch 4electrodes of each ci) any desired Aconstant potential relation between the grid and 'the' filament.

Fig. 3 is similar to thel arrangement shown in Fig. 2 except that the thermionic device 42 is arranged with ."re'spect to a rheostat 43 soy that the potential of the grid electrode'is varied iii-'accordance with the changes 'in-the' left 'hand resistance of the rheostat 43. The Iplate electrode of the thermionic device 4 2 is connected to a resistance 44 connected between the terminals of the filament of this device, and a constant diffrence'of potential is maintained between t e late -and filament.

T e arrangement shown 'inl Fig.. 4 is afof the thermionic devices 46, 47 and 48 are connected in series with a battery 49, the filament of the thermionic device 47 being connected to the positive end of the battery 49. -As in the previous illustrations, there is connected in the` filament circuits of each .of the thermionic devices 46, 47 and 48 a double rheostat 50, 51 and 52, respectively. The grid electrode of the thermionic deyso ila',

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vice 46 is connected to the negative pole` of the b..ttery 49 and the left hand resistance of the rheostat 50, thepotential drop between the grid and filament being determined by the amount of this resistance which is connected in circuit, The grid elec- 'trode of the thermionic device 48 is also connected directly to the negativepole of the battery 49. With such an arrangement, the potential between the grid and' filament of the thermionic ,device 4S is not only dependent upon the effective resistance of the rheostat .52, but is also kde endent upon the effective resistance of the iiheostat 50 and of the filament of device 46. It is thus seen that bA the use of such controlled means a igherpotential can be obtained on the grid electrode of the thermionic device 48 than would be obtained if the grid electrode was connected to the left hand resistance of the rheostat 52. vFurthermore, on account of the self-compensating feature of the rheostats the bias. of each grid ma be regulated without affecting the bias o the other grid-s. The otntials of the plate the devices is also varied in a manner similar to that already described. v

Although the invention hasbeen disclosed rent'cin the cathode circuit.

audaces a source of' potential for said tube, and

means included in `the cathode circuitfor effecting changes in the potentials applied to said control and plate electrodes without changing the current in the cathode circuit.

'2. In combination, a vacuum tube havinga. cathode, a control and a plate electrode, a source of potential for said tube, a double rheostat included in the cathode circuit, and

'a single control element for changing the resistance of' said rheostat to effect changes in. the potential applied to' the control and plate electrodes Without changing the cur- 3. I n combination, a vacuum tube having a cathode, a grid and a plate electrode,- a source of potential for said cathode, a resistance in series with said cathode and means for varying said resistance so that the potential applied to said control electrode maybe Varied without causing a ehangein the current through said cathode.

4. In combination, a vacuum tube having a cathode, a grid electrode and an anode, a source of potential for said cathode, a pair of rheostats series with said cathode, and

a single control element for simultaneously varying one of said rheostats in accordance with the change in the potential applied to the grid -electrode as determined by said other rheostat.

5. In combination, a multi-stage vacuum tube amplifier, each of'said amplifiers having a cathode, a grid and a plate electrode,

asource ofi otentia, means included-in the cathode circuitv of each-of said .vacuum tubes comprising a double rheostat, and a single control element for said rheostats for varying the potential applied between said cathode and said grid electrodes .and for maintaining the current in said cathode circuit constant.

6. In combination, a multi-stage vacuum tube amplifier, each of said amplifiers having a cathode, a grid and'a plate electrode, a source of potential, means included in the cathode circuit of each of said vacuum tube amplifiers comprising a resistance serving to determine the fractional part of the source of potential to be applied between said cathode and said grid-electrode,"a resistance serving to adjust the cathode current, and

means common to said resistances for maintaining the cathode current constant irrespective of changes in the potentials applied to said grid electrode.

Y7. In combination, a multi-stage vacuum tube amplifier, each of said amplifiers hav- .ing a filament, a-grid and a plate electrode, a source of potential, the filaments of each of said tubes being serially connected with said source 'of potential, a double rheostat associated with each of saidV filaments for changing the potential applied between the grids and the filaments Without varying the lament current, and circuit connections for applying a potential between the grid electrode and the filamentof one tube due both to the resistance of'the associated rheostat and the resistance of the rheostat of. another tube independent of changesv in the resistance of the. rheostatof said other tube.

In witness whereof, I hereunto subcribe my-name this 28th day of November, A.A D.,

HENRY P. cLAUsEN. 

